Collapsing tap and similar tool.



F. A. taamewow.

COLLAPSING TAP AND SIMILAR TOOL.

APPLICATION FILED IUNE 1?. I915- 1 ,200, 1 81; Patented Oct. 3, 1916 are.

FRANKLIN A. Eaanvo'ron, or STAILE'LON, new YORK.

COLLAPSING TAP AND SIMILAR, TOOL.

Specification of Letters Patent.

Patented Get. 3, 1916.

v Application filed June 17, 1915. Serial No. 34,645.

To all whom it may concern:

Be it known that I, FRANKLIN ALFRED E RINGTON, a citizen of the United States of America, residing at Stapleton, in the county of Richmond, State of New York, have invented certain new and useful Improveine'nts in Collapsing Taps and Similar Tools, of which the following is a specification i My invention relates broadly to interchangeable means for rigidly determining the cutting diameter of a tap, reamer or similar tool; and more particularly to means for loosely centering the cutting jaws in the rigidly held body of such a tap, reamer, etc, in such a manner that the jaws may accurately perform theirfunction', even should the axis of the hole inthe work (to be tapped or reamed) be slightly out of line with the axis of the body of my device; also, to means for equalizing the support of said jaws when in the cutting position; and I have preferably shown'the application of my invention as a means of collapsing a plurality screw-cutting chasers by utilizing the spiral coaction of the screwthreads during the cutting operation of the teeth of the chasers with the threads thereby cut in the work in such a manner as to move longitudinally of the supporting body, either the ch'asers, or the means that determine their cutting diameter, thereby collapsing the chasers, to permit the tap being withdrawn from the tapped hole in the work, without stopping or reversing the direction of rotation of the driving means; and my invention further consists in the novel details of improvement that will be more fully hereinafter set forth, and then pointed out in the claims.

Reference is to be had to the accompanying drawings, forming a part hereof,

wherein Figure 1 represents a vertical crosssection of a device embodying my invention, the partsbeing shownin' the cutting position of the aws; Fig. 2 is a horizontal cross-' section of Fig. 1 on the line 22, showing a preferred arrangement of the intersecting, self-centering thrust-blocks; Fig. 3 is a similar view to Fig. 1, except the parts are shown in the collapsed position; and Fig. 4 is a plan view of the cutting end of the device showing the jaws in collapsed position.

Similar numerals and letters of reference indicate corresponding parts in the several views.

A body 1 is shown provided at its rear or lnner end with a shank 1 for connection with suitable driving means; at the outer end the periphery of the body is indented by amultiplicity of longitudinal grooves 1 adapted to receive jaws orchasers 2. The bottom surfaces of the longitudinal grooves are pierced by'a longitudinal series of transverse bores 1, which preferably register with those of the opposed longitudinal groove; so that when I place thrust-blocks 3 1n said transverse bores the opposite ends .of

thethrust-blocks will. bear upon the inner surfaces of the opposedjaws 2. The outer ends of the thrust-blocks 3 extend outwardly beyond the bottom surfaces of the longitudinal grooves 1 to provide in each of said longitudinal grooves a longitudinal series of projections with indentures therebetween, the outer end-surfaces of the thrust-blocks 3 providing external thrustfaces 3, adapted to cooperate with a corresponding longitudinal series of projections and indentures provided on the inner or under surface of the jaws 2, the inner surfaces of the jaw-projections providing internal thrust-faces 2 adapted to bear upon the external thrust-faces 8 when the jaws 2 are in the cutting position shown in Fig. 1.

I have preferably arranged the transverse.

bores 1 in the opposed grooves 1 to register with each other, so that should one member of either pair of jaws 2 receive an excessive side thrust or heavy out (such as might occur if the hole in a piece of work was out of line with the axis of my device), the opposed jaw will yield in unison, and both jaws move transversely of body 1 during the cutting operation, without altering the cutting diameter of the opposed jaws 2. To limit this self-centering action of the jaws 2 I may slip stop-collars 4 over the extended ends of the thrust-blocks" 8, the thickness of the stop-collars 4: determining the amount of float, or transverse movement, it is desirable to permit to jaws 2. z

chasers with equal rigidity at that point.

To do this, I have preferably enlarged one 7 of the outer transverse bores 1 sufliciently to receive an outer thrust-block 5, having a transverse bore 5 of greater diameter than that of the component outer thrustblock 6, which I have shown intersecting the enlarged outer thrust-block 5 through its bore 5; and around the outer ends of outer thrust-block 6 I have placed side-stop collars at which also serve to close the outer ends of grooves l under the jaws 2, to prevent the entrance of chips, etc. As above stated, the side-stop collars 4 are left thin enough topermit the desired float to the jaws 2. By this construction all of the four jaws shown in this device are equally supported, and have a limited transverse movement independently of body 1, through the slip-joint intersection of the thrust-blocks 5 and (i, at the point of intersection of the axes of the thrust-blocks with the axis of the body 1.

The jaws 2 are preferably held in their respective grooves 1 concentrically of body 1 by a spiral band spring 7, the ends of which are joined together; and the jaws 2 are shown provided with a spring-groove- 2 extending across the outer surface of the jaws. Tl'ie jaws 2 are sufliciently extended beyond the periphery of body 1 to permit the retaining spring 7 to exert a concentric pressure upon them, even when in the collapsed position. An abutment or pin 8 is provided (see Fig. 4) for the spring 7 to slip over, and thereby hold the jaws in the cutting position; and I believe it is preferable to provide a multiplicity of these abutments 8, to insure holding the aws 2 evenly in the cutting position. I

To facilitate the manufacture of the device and to provide a true hardened surface for all the jaws 2 to abut against when presented against the work, I have preferably slipped a hardened ring 9 over the body 1, said ring abutting against a shoulder 1 provided on body 1 for that purpose. The jaws 2 are then slipped into their respective grooves 1, the rear surfaces of the jawprojections being preferably beveled to run up over the projecting ends of the thrustblocks 3, as the jaws are pushed inwardly along grooves 1"; and the front surfaces of the ja'wpi'ojections are shown extending at right angles to the axis of body 1, to catch against the projecting thrust-blocks 3 when the jaws 2 have moved forward to the collapsed position (see Fig. The spring? is preferably slipped over the jaws 2 while they are in the collapsed position shown in Fig. 3, the spring 7 passing over the screw-threaded portipns until the spring meshes with the transverse rooves 2 provided in the jaws to receive it.

To facilitate the drawing back of the jaws 2 from the collapsed into the cutting position, I have shown a collar 10 rotatable and longitudinally movable on shank 1,

said collar 10 being provided with an internal recess 10, or similar means, to connect one end of a series of springs 11 with said collar, the other ends of said springs being hooked under the rear projections of the jaws 2. This affords a yielding link between j aw's' 2 and collar 10.

To bring the parts of the device into the cutting position shown in Fig. 1, the op erator pushes the collar 10 inwardly along shank 1, and the springs 11 pull the jaws 2 and spring? inwardly along body 1, the sloping sides of the jaw-projections ascending the thrust-blocks 3 until the internal thrust-faces 2 of the jaws slide into line, transversely of body 1, with the external thrustfaces of blocks 3, said thrust-faces continuing to increase their bearing upon each other until the rear ends of the jaws 2 abut against thethrust-ring 9, whereupon the spring 7 shall have slippedcover the abutment 8, thereby locking the parts in the cutting-position shown in Figs. 1 and 2. hen it is desired to change the cutting diameter offthe jaws 2, the thrust-blocks 3 can be shortened, or said thrust-blocks can be readily replaced by longer ones.

When applying my invention to a collapsing tap having its chasers 2 externally screw-threaded as shown in the drawings, upon the rotation of either the device or of a suitable piece of work having a suitable aperture to be tapped, the chasers 2 will cut screw-threads into the walls of said aperture in the work upon the presentation of the device thereagainst; and the position of the chasers '2 relatively to body 1 will remain constant until the relative movement of the work and the device toward each other is stopped by any suitable means,as, for instance, by using the outer end 1 of the body as a stop to encounter the bottom surface of the aperture being threaded, whereupon the continued rotation of the rotative member (either body 1, or the work being operated on) will cause the chasers 2 to continue cutting, while at the same time the screw-threads of the chasers 2 will drawthe chasers 2 longitudinally of body 1 during the cutting operation, independently of the thrust-blocks 3, by the spiral coaction of the screw-threads of the chasers with the threads already cut in the work, until the internal thrust-faces 2 of the chasers 2 pass out of line, transversely of body 1, with the external thrust-faces 3 of the thrustblocks 3, whereupon the jaws 2 will slide inwardly radially of body 1, the projections 2 of the chasers passing within the plane of their respective associate external thrustfaces 3 into the indentures therebetween, and this inward radial movement of the chasers 2 continues during the collapsing operation until the cutting teeth clear the threaded walls of'the aperture in the Work,

whereupon the device can be withdrawn from the threaded and. completed aperture, without stopping or reversing the direction of rotation of the rotative member (either the work or the device).

Having now described my invention, what I claim is 1. The combination with a body having a plurality of longitudinal grooves in its periphery and cutting jaws located in said grooves, the bottom surfaces of the grooves being pierced by a longitudinal series of transverse bores, of a plurality of thrustblocks located in said transverse bores under and independent of said jaws and projecting outwardly beyond the bottom surfaces of the grooves, said transverse bores in the opposed grooves registering with each other to permit a limited movement of said thrust-blocks and jaws transversely of the body during the cutting operation, substantially as described.

2. The combination of a body having a plurality of longitudinal grooves in its periphery and cutting jaws located in said. grooves, the bottom surfaces of the grooves being pierced by a longitudinal series of transverse bores which intersect corresponding transverse bores leading from the bottom surfaces of the other grooves, of thrustblocks located in said transverse bores, the axes of said thrust-blocks intersecting each other to give equal support under said jaws,

substantially as described.

3. The combination with a body having a plurality of longitudinal grooves in its periphery and cutting jaws located in said grooves, the bottom surfaces of each of said grooves being pierced by a longitudinal series of transverse bores which intersect corresponding transverse bores leading from.

the bottom surfaces of the other grooves, of thrust-blocks located in said transverse bores and intersecting each other by a slip-joint that provides a limited independent movement of each member transversely of the body to permit a corresponding transverse movement of said jaws during'the cutting operation, substantially as described.

4. The combination with a body having a plurality of longitudinal grooves in its periphery and cutting jaws located in said grooves, the bottom surfaces of the grooves being pierced by a longitudinal series of transverse bores, of a plurality of thrustblocks located in said transverse bores under and independent of said jaws and projecting outwardly beyond the bottom surfaces of the grooves, said transverse bores in the opposed grooves registering with each other to permit a limited movement of said thrustblocks and jaws transversely of the body during the cutting operation, and means to limit said transverse movement of the jaws, substantially as described.

5. The combination with a body having a plurality of longitudinal grooves in its periphery and cutting jaws located therein and movable longitudinally therealong during' the cutting operation to collapse said jaws, with a collar having a limited longitudinal movement along said body, and resilient means toconnect said jaws with said collar to permit said collar to elastically expand said jaws to the cutting position, substantially as described. 7

FRANKLIN A. ER'RINGTON Witnesses:

F. I. GooDRIoH, L. E. MANNING. I

Oofle: of this patent may be obtained for five cents each, by addressing the Commissioner of Patents Washington, D. C. i 

